# Burden of RSV-Associated Inpatient Care and Emergency Service Utilization in Two German Pediatric Centers Across Six Seasons Including the First Nirsevimab Year

## TL;DR

This study shows that RSV caused consistent hospital and emergency care use over six seasons, with severe cases only in unimmunized infants during the first year of a new vaccine.

## Contribution

The study provides real-world evidence of RSV healthcare utilization and the impact of the first year of nirsevimab immunoprophylaxis in Germany.

## Key findings

- RSV hospitalizations decreased in the first year of immunization, with fewer infants under one year affected.
- Severe RSV disease occurred only in unimmunized infants during the first nirsevimab season.
- RSV season onset was delayed in the first year of immunization, but overall severity remained stable.

## Abstract

What are the main findings?
RSV caused sustained emergency department and inpatient utilization across six seasons.Overall severity remained stable; severe RSV disease (PICU admission or invasive respiratory support) occurred only in unimmunized infants during the first Nirsevimab season.

RSV caused sustained emergency department and inpatient utilization across six seasons.

Overall severity remained stable; severe RSV disease (PICU admission or invasive respiratory support) occurred only in unimmunized infants during the first Nirsevimab season.

What are the implications of the main findings?
RSV continues to impose a relevant outpatient and ward-level healthcare burden despite stable population-level severity.Integrated inpatient and emergency department data enable nuanced assessment of preventive strategies beyond incidence alone.

RSV continues to impose a relevant outpatient and ward-level healthcare burden despite stable population-level severity.

Integrated inpatient and emergency department data enable nuanced assessment of preventive strategies beyond incidence alone.

Background/Objectives: Respiratory syncytial virus (RSV) is a major cause of infant respiratory morbidity, yet real-world data on healthcare utilization following universal immunoprophylaxis remain limited. Methods: We retrospectively analyzed RSV-positive inpatient and emergency department (ED) encounters from two German tertiary pediatric centers across six seasons (2019/20–2024/25). Augsburg contributed inpatient data for 2022/23–2024/25, including immunization status and severity metrics, while Erlangen provided inpatient and ED data across all seasons. Results: In Augsburg, RSV hospitalizations were higher in pre-immunization seasons than in 2024/25, accompanied by a reduced proportion of infants < 1 year. RSV season onset occurred later in 2024/25, while severity metrics remained stable. Among infants < 1 year hospitalized in 2024/25, all severe cases occurred in unimmunized infants; no severe outcomes were observed among the small number of immunized cases. Conclusions: Integrated multicenter data descriptively coincide with reduced RSV hospitalization burden following immunoprophylaxis introduction, without evidence of increased disease severity.